Paul is explaining the attitudes we must avoid if we are going to accept one another as he says. In Verse 3 you have that:
The man who eats everything must not look down on him who does not . . . (Romans 14:3a)
That is the first thing. In other words, the strong must not reject the believer who is still struggling, who is still weak. When it says, “look down,” here , it is really saying “push him out.” I am sure you have seen that happen. One of my friends loves to announce that he has been, “kicked out of some of the best churches in town,” purely because they don’t appreciate his attitude.
What Paul is saying is that the strong must not push him out—or more literally, “despise;” him. They must not exclude him. I can think of several ways this could happen: First, this “stronger,” more “mature” person, must never look at this “weaker” brother in a disdainful or contemptuous way. He must never let himself look down on them.
I see this many times. I think it is a tendency many of us have who feels we are free in certain of these areas. We tend to regard those who are not yet free as weaklings.
Nevertheless, we are not to regard them as being deliberately that way, as if it is their own fault that they are weaker. We get offended when they do not behave as freely as we think they should. This is wrong. Paul says, “The strong must not reject the weak.” You must not think the wrong thing about him. You must not say the wrong things about him. You must not ridicule him.
I almost did not marry Patrice. You see, when we were dating she invited me to attend a “Wine Festival” that was going on in town. Now, I had never been to one and we went with another couple she worked with. As we wandered through the festival, I was surprised how uncomfortable I was—and how relaxed she was.
I later said to her, “I don’t think we should get married because we are so different.” She replied, “Well, I think we work well together. I can get you to relax a little, and you can teach me to pray more.” Well, she put up with me and accepted me as I was. I guess it worked because it has been almost 30 years together (with four kids and four grandchildren).
If interested, you can download the entire study of The Letter to Christians at Rome